CANCER COUNCIL AUSTRALIA has revised dramatically upwards its estimate of alcohol's contribution to new cancer cases and issued its strongest warning yet that people worried by the link should avoid drinking altogether.

New evidence implicating alcohol in the development of bowel and breast cancer meant drinking probably caused about 5.6 per cent of cancers in Australia, or nearly 6500 of the 115,000 cases expected this year, a review by the council found. This was nearly double the 3.1 per cent figure it nominated in its last assessment, in 2008.

The council's chief executive, Ian Olver, said the updated calculations revealed breast and bowel cancer accounted for nearly two-thirds of all alcohol-related cancers, overtaking those of the mouth, throat and oesophagus.

''The public really needs to know about it because it's a modifiable risk factor,'' said Professor Olver, calling for awareness campaigns to alert people to the link. ''You might not be able to help your genes but you can make lifestyle choices.''

Professor Olver said public advice should not conflict with the National Health & Medical Research Council's 2009 recommendation people should drink no more than two standard alcohol units daily, already half the previous safe threshold for men.

But people should also be told there was no evidence of a safe alcohol dose below which cancer-causing effects did not occur - either from direct DNA damage, increased oestrogen levels or excessive weight gain. ''If you want to reduce your cancer risk as far as possible [abstinence] would be the option you have,'' he said.

Public advice was especially important, Professor Olver said, because studies that suggested alcohol could protect against heart disease were increasingly being challenged by new findings that people gave up drinking when they became ill or old - meaning any potential benefits of moderate alcohol use for cardiovascular health had probably been oversold.

Western Australia last year began screening government-funded advertisements about the link between cancer and alcohol and Victoria is understood to be about to start. But spokespeople for the Cancer Council NSW and Cancer Institute NSW yesterday said there were no immediate plans for a similar campaign here.

Mike Daube, the convener of the Public Health Association of Australia's alcohol expert group, said he would write today to the Australia and New Zealand Food Regulation Ministerial Council, which is meeting this month, to request it mandate health warnings on bottles.

''I'm not talking about tobacco-style warnings but at the moment there's no requirement for any health advice on alcohol packaging, and that's wrong,'' said Professor Daube, from Curtin University.

He said the council's findings also had implications for taxation of alcohol, which is on the agenda at the tax summit in October.